In August 2016, the Company entered into a lease agreement for office and lab space, which consists of approximately 32,813 square feet of rental space in South San Francisco, California. The office space lease is classified as an operating lease. The initial lease term commenced in May 2017 and ends in April 2025, with rent payments escalating each year. The Company has options to extend the lease for additional years, but the exercise of the option was not reasonably certain.

In connection with the lease, the Company maintains a letter of credit for the benefit of the landlord in the amount of $0.4 million, which is recorded as restricted cash in the condensed consolidated balance sheets. On March 10, 2023, Silicon Valley Bank, or SVB, was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation, or FDIC, as a receiver. On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVB's customer deposits and certain other liabilities and acquired substantially all of SVB's loans and certain other assets from the FDIC. As required by the landlord, the Company replaced the letter of credit issued by SVB with a letter of credit from a different financial institution.

The operating lease expense for the three and nine months ended September 30, 2023 and 2022 was $0.4 million, $1.2 million, $0.4 million and $1.5 million, respectively.

Aggregate future minimum rental payments under the operating leases as of September 30, 2023, were as follows (in thousands):


Remaining three months ending December 31, 2023	$	656
Year ending December 31, 2024		2,670
Year ending December 31, 2025		891
Total lease payments		4,217
Less: Imputed interest		(258	)
Operating lease liabilities	$	3,959